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HELCOM Baltic Sea Action Plan - A regional programme of measures for the marine environment based on the Ecosystem Approach 总被引:1,自引:0,他引:1
Hermanni Backer Juha-Markku Leppänen Kaj Forsius Jukka Mehtonen Minna Pyhälä Hanna Paulomäki Tarja Haaranen 《Marine pollution bulletin》2010,60(5):642-649
The Helsinki Commission (HELCOM) Baltic Sea Action Plan, adopted by the coastal countries of the Baltic Sea and the European Community in November 2007, is a regional intergovernmental programme of measures for the protection and management of the marine environment explicitly based on the Ecosystem Approach. The Action Plan is structured around a set of Ecological Objectives used to define indicators and targets, including effect-based nutrient input ceilings, and to monitor implementation. The Action Plan strongly links Baltic marine environmental concerns to important socio-economic fields such as agriculture and fisheries and promotes cross-sectoral tools including marine spatial planning. Due to complementarities with the European Union (EU) Marine Strategy Framework Directive, the Action Plan is in essence a pilot for this process without neglecting the important role of the Russian Federation - the only Baltic coastal country not a member of the EU. 相似文献
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The effect of elevated nitric acid concentrations on cloud particle number concentrations and sizes of mixed phase cirrus cloud (containing both supercooled liquid and frozen ice particles) is studied using a detailed multicomponent condensation model. Our model calculations suggest that high nitric acid volume mixing ratios (VMRs), corresponding to upper tropospheric measurements, can increase the ice crystal number concentrations substantially especially in the case of freezing of non-activated solution droplets (as opposed to freezing of supercooled cloud droplets). This is due to increased droplet sizes caused by nitric acid absorption and the resulting uptake of water. 相似文献
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Diversity of meiofauna in the lacustrine profundal zone: Bathymetric differences and influence of environmental factors 总被引:2,自引:0,他引:2
Jukka Särkkä 《Aquatic Sciences - Research Across Boundaries》1993,55(3):197-205
The diversity and species richness of total meiofauna, Harpacticoida and Oligochaeta in relation to depth and other environmental variables were studied at nine stations and in two profundal depth zones in Lake Päijänne which includes both oligotrophic and eutrophicated or organically loaded areas.Diversity was on average higher in the upper part of the profundal zone than at maximum depths. This may show that the greater temporal stability in temperature at greater depths does not surpass the effect of the lower temporal stability in oxygen content. The productivity factor may be a more important reason for the bathymetric difference in diversity than the stability factor. Diversity in the lower profundal zone shows a negative correlation with variables indicating pollution while in the upper profundal zone a positive one with those variables, thus emphasizing the importance of the production factor in determining diversity in the upper profundal. Diversity was higher within the oligochaetes than within the harpacticoids, which may imply that oligochaetes have a longer evolutionary history as part of the lacustrine benthic system.Of the environmental variables, phytoplankton biomass had the highest influence on total diversity in the lower profundal zone, oxygen being next in importance. The sedimentation of organic matter was most important in the upper part of the profundal zone, where oxygen did not have any significant effect on diversity. Some explaining factors determining bathymetric diversity differences are discussed in relation to the theoretical expectations. 相似文献
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Modern assessment and monitoring of aquatic ecosystems is increasingly based on biota and the “reference condition” approach,
in which the observed values (O) of biological variables are compared to those expected in the absence of human disturbance (E). To use this approach, correct estimation and validation of reference conditions are critical. Because appropriate modern
or historical data are never available for this approach, palaeolimnological data offer an alternative. We used a calibration
data set from 73 profundal sites in semi-pristine Finnish lakes to construct a regression model for estimating expected values
for the chironomid Benthic Quality Index (BQI)—a macroinvertebrate metric widely used in bioassessment—from environmental
variables that are insensitive to human disturbance. For comparison, reference values were estimated using the European legislative
rationale based on a priori lake typology. Performance of the alternative approaches was assessed by internal ‘leave-one-out’
cross-validation using the calibration set and by external cross-validation using independent palaeolimnological data on BQI
values representing the historical pristine status of 24 lake basins. Additionally, for 19 of these sites, which vary in their
degree of human impact, the ratio of present BQI to that in pristine condition, which shows the degree of actual change, if
any, was calculated from palaeolimnological data and compared with the O/E ratios based on the present chironomid data and estimated E. A linear regression model with mean depth and mean/maximum depth ratio as independent variables estimated the reference
values of BQI much closer to the observed ones (r
2 = 0.58, RMSEP = 0.65 and r
2 = 0.71 RMSEP = 0.55; for internal and external cross-validation, respectively) than did the typology approach (r
2 = 0.28, RMSEP = 0.86; r
2 = 0.10, RMSEP = 0.97). The regression approach also yielded O/E ratios more similar to the actual ones (r
2 = 0.79, RMSEP = 0.09) than did the typology approach (r
2 = 0.62, RMSEP = 0.23). Our results strongly support the use of lake morphometric variables and modelling instead of categorical
lake typology for the establishment of reference conditions for profundal macroinvertebrate communities and demonstrate the
utility of palaeolimnological data in the validation of reference values and assessment methods. 相似文献
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Lathrap introduced the concept of lateral channel migration of the meandering rivers as a potential factor for human community dynamics in the Upper Amazon. Nevertheless, the dynamics considered by Lathrap is restricted to particular floodplains. He payed no attention to a large scale fluvial phenomenom: the sudden river relocations (avulsion), which also profoundly affected the Upper Amazon cultures. We present here a historical case study analyzing a river floodplain avulsion at the Middle Ucayali River during the late 1700s, causing the abandonment of a settlement called San Miguel de Cunibos and probably leading to the massive migration of the Cunibos Indians. Furthermore, we argue that similar situations have frequently occurred during the human history of the Upper Amazon, and thus these fluvial phenomena should be taken into consideration in future archaeological and ethnohistorical studies. © 1996 John Wiley & Sons, Inc. 相似文献
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ABSTRACT Taxi trajectories from urban environments allow inferring various information about the transport service qualities and commuter dynamics. It is possible to associate starting and end points of taxi trips with requirements of individual groups of people and even social inequalities. Previous research shows that due to service restrictions, boro taxis have typical customer destination locations on selected Saturdays: many drop-off clusters appear near the restricted zone, where it is not allowed to pick up customers and only few drop-off clusters appear at complicated crossing. Detected crossings imply recent infrastructural modifications. We want to follow up on these results and add one additional group of commuters: Citi Bike users. For selected Saturdays in June 2015, we want to compare the destinations of boro taxi and Citi Bike users. This is challenging due to manifold differences between active mobility and motorized road users, and, due to the fact that station-based bike sharing services are restricted to stations. Start and end points of trips, as well as the volumes in between rely on specific numbers of bike sharing stations. Therefore, we introduce a novel spatiotemporal assigning procedure for areas of influence around static bike sharing stations for extending available computational methods. 相似文献
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Tomasz Janik Marek Grad Aleksander Guterch Ryszard Dadlez Jukka Yliniemi Timo Tiira G. Randy Keller Edward Gaczyski CELEBRATION Working Group 《Tectonophysics》2005,411(1-4):129-156
The large-scale CELEBRATION 2000 seismic experiment investigated the velocity structure of the crust and upper mantle between western portion of the East European Craton (EEC) and the eastern Alps. This area comprises: the Trans-European Suture Zone, the Carpathian Mountains, the Pannonian Basin and the Bohemian Massif. This experiment included 147 chemical shots recorded by 1230 seismic stations during two deployments. Good quality data along 16 main and a few additional profiles were recorded. One of them, profile CEL03, was located in southeastern Poland and was laid out as a prolongation of the TTZ profile performed in 1993. This paper focuses on the joint interpretation of seismic data along the NW–SE trending TTZ–CEL03 transect, located in the central portion of the Trans-European Suture Zone. First arrivals and later phases of waves reflected/refracted in the crust and upper mantle were interpreted using two-dimensional tomographic inversion and ray-tracing techniques. This modelling established a 2-D (quasi 3-D) P-wave velocity lithospheric model. Four crustal units were identified along the transect. From northwest to southeast, thickness of the crust varies from 35 km in the Pomeranian Unit (NW) to 40 km in the Kuiavian Unit, to 50 km in the Radom–Łysogóry Unit and again to 43 km in the Narol Unit (SE). The first two units are thought to be proximal terranes detached from the EEC farther to the southeast and re-accreted to the edge of the EEC during the Early Palaeozoic. The origin of the remaining two units is a matter of dispute: they are either portions of the EEC or other proximal terranes. In the area of the Polish Basin (first two units), the P-wave velocity is very low (Vp < 6.1 km/s) down to depths of 15–20 km indicating that a very thick sedimentary and possibly volcanic rock sequence, whose lower portion may be metamorphosed, is present. The velocity beneath the Moho was found to be rather high, being 8.25 km/s in the northwestern portion of the transect, 8.4 km/s in the central sector, and 8.1 km/s in the southeastern sector. 相似文献
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Leena K. L. Nurminen Jukka A. Horppila 《Aquatic Sciences - Research Across Boundaries》2002,64(2):198-206
The objective of the present study was to investigate the importance of emergent macrophytes as refugia in lakes of different trophic status. Furthermore, the effect of water quality on diel changes in the distribution of littoral cladocerans was of interest, with special attention paid on diurnal fluctuations of filter feeder communities, induced by pH changes under a heavy phytoplankton bloom. The study was conducted by investigating littoral cladoceran populations in different zones (inside, at the edge and outside the macrophyte stands) in two basins with divergent water quality. No tendency towards diurnal migration related to emergent macrophytes was observed in the clear-water, mesotrophic Isontalonselkä basin. The dominating cladoceran, Daphnia spp., formed highest densities during daytime in the outer zone. Meanwhile, strong nocturnal cladoceran density peaks in all zones, simultaneous with lowered pH, were witnessed in the very turbid, hypertrophic Kirkkojärvi basin. Reverse horizontal migration was observed in large-bodied filter feeders, Limnosida frontosa and Sida crystallina, conceivably due to predation avoidance from young-of-the-year fish aggregating within the vegetation during the day. 相似文献